Abstract [en]

Mammalian prey species are able to detect predator odors and to display appropriate defensivebehavior. However, there is only limited knowledge about whether single compounds of predatorodors are sufficient to elicit such behavior. Therefore, we assessed if predator-naïve CD-1 mice(n = 60) avoid sulfur-containing compounds that are characteristic components of natural predatorodors and/or display other indicators of anxiety. A 2-compartment test arena was used to assessapproach/avoidance behavior, general motor activity, and the number of fecal pellets excretedwhen the animals were presented with 1 of 6 predator odor components in one compartment anda blank control in the other compartment. We found that 2 of the 6 predator odor components(2-propylthietane and 3-methyl-1-butanethiol) were significantly avoided by the mice. The remaining4 predator odor components (2,2-dimethylthietane, 3-mercapto-3-methylbutan-1-ol, 3-mercapto-3-methylbutyl-1-formate, and methyl-2-phenylethyl sulphide) as well as a nonpredator-associatedfruity odor (n-pentyl acetate) were not avoided. Neither the general motor activity nor the numberof excreted fecal pellets, both widely used measures of stress- or anxiety-related behavior, weresystematically affected by any of the odorants tested. Further, we found that small changes in themolecular structure of a predator odor component can have a marked effect on its behavioralsignificance as 2-propylthietane was significantly avoided by the mice whereas the structurallyrelated 2,2-dimethylthietane was not. We conclude that sulfur-containing volatiles identified ascharacteristic components of the urine, feces, and anal gland secretions of mammalian predatorscan be, but are not necessarily sufficient to elicit defensive behaviors in a mammalian prey species.